Clinical surveys and therapeutic trials in children with kidney diseases are being conducted by the International Study of Kidney Disease in Children (ISKDC) in which 23 clinics in 12 countries are participating. Systematic retrospective and prospective surveys are being done on the natural history of the major kidney diseases of children including the nephrotic syndrome, familial nephritis, recurrent hematuria, and membranous nephropathy. Therapeutic drug trials in children are (1) in progress on the effects of a) azathioprine in anaphylactoid purpura nephritis; b) prednisone in membranoproliferative glomerulonephritis; c) prednisone in minimal change nephrotic syndrome; d) cyclophosphamide in focal, segmental sclerosis; and (2) in preparation on a) streptokinase in the hemolytic-uremic syndrome; b) and azathioprine in lupus nephritis. A register of patients with kidney disease seen in the participating clinics has been established.